Non-polar Blackgates replace polarized? - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 7th February 2009, 06:31 PM   #1
reiver is offline reiver  United States
diyAudio Member
 
Join Date: May 2008
Default Non-polar Blackgates replace polarized?

I'm was looking at the analog pre-amp-out circuit board on my receiver (Denon AVR-3805) and noticed that the signal passes through two electrolytic capacitors before it reaches each RCA jack.

These caps are prime to upgrade obviously, but here's my question:


The stock caps are 22mf/50v polarized caps, as you can see on the attached schematic. Can I replace these with non-polarized 22mf Blackgate electrolytics, or is there reason the stock ones are polarized?

-Bryan
Attached Images
File Type: jpg circuit.jpg (95.2 KB, 191 views)
  Reply With Quote
Old 7th February 2009, 06:49 PM   #2
SQLGuy is offline SQLGuy  United States
diyAudio Member
 
Join Date: Jan 2009
Electrically, yes you can use them.

Bipolar electrolytics are actually two electrolytic capacitors connected in series in one case. So, instead of 1 22uF cap, you're putting in 2 44uF caps in series (which divides the effective capacitance but protects both caps from reveresed polarity).

I would say to bypass such a coupling cap with a good quality foil cap (.1 uF or so). i.e. Put in the bipolars, but also put a .1uF Wima or something in parallel with each of them.
  Reply With Quote
Old 7th February 2009, 08:31 PM   #3
MRupp is offline MRupp  Germany
diyAudio Member
 
MRupp's Avatar
 
Join Date: Dec 2003
Location: Frankfurt area
Quote:
Bipolar electrolytics are actually two electrolytic capacitors connected in series in one case.
All electrolytic caps are actually 2 caps in series. Polar caps have only one foil that was formatted to build an oxide layer of the required thickness while the second foil has just the thin oxide layer that forms under atmospheric conditions - and survives 1 - 2 Volts. The non-polar cap has both foils formatted to sustain the nominal voltage.
__________________
Martin Rupp
  Reply With Quote
Old 8th February 2009, 03:06 AM   #4
reiver is offline reiver  United States
diyAudio Member
 
Join Date: May 2008
Default re:

NP caps block DC while polarized ones pass it.

What I was hinting at was whether this type of circuit actually requires polarized caps...and if switching to NP versions could cause some instability in the circuit.
  Reply With Quote
Old 8th February 2009, 03:42 AM   #5
SQLGuy is offline SQLGuy  United States
diyAudio Member
 
Join Date: Jan 2009
Default Re: re:

Quote:
Originally posted by reiver
NP caps block DC while polarized ones pass it.
No, that's entirely wrong. The only type of cap that passes DC is a bad one.

Non-polarized caps can take DC offset in either direction. Polarized caps can take it in one direction only.

If you take your 22uF 50V NP's, you can apply, for example, +35V to one leg and ground to other, or vice versa, and in either case things will be just fine.

If you try the same thing with a polarized cap, things will only be fine with +35V on the + leg. If you reverse it, the cap will start to get hot, and will eventually vent or explode.
  Reply With Quote
Old 8th February 2009, 03:02 PM   #6
reiver is offline reiver  United States
diyAudio Member
 
Join Date: May 2008
Default re:

Thanks for the info, I didn't know NPs could pass DC, explains some things about modding that never seemed to click with me. Time to order some Blackgates....
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Polarized to non-polar capacitor wiring mjarve Parts 8 2nd April 2012 03:27 PM
Black Gate Standard Polarized or PK Mini Polarized = Rubicon YK or YXE kurtbauer Parts 1 21st August 2008 06:50 AM
Where can I buy Blackgates??? K-amps Parts 3 25th February 2005 01:07 AM
Do Blackgates age? ainami Parts 4 10th January 2005 10:34 AM
Can I make a Non-Polar Electrolytic using two polar ones PaulHilgeman Parts 6 10th February 2003 12:07 AM


New To Site? Need Help?

All times are GMT. The time now is 12:58 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2